Question

30. The number of terms of the A.P 7,12,17 ,....,57 are
a) 5
b) 9
c) 10
d) 11​

Answer 1

Answer:

option d

Step-by-step explanation:

by using formula a subscript n =a+(n-1)d

a-first term d-common difference (a2-a1)

Answer 2

Answer:

9

Step-by-step explanation:

here,

a = 7

d = 5 (12-7)

tn = a + (n-1) d  

57 (last term aka. tn) = 7 + (n-1) 5

50 (57-7) = 5n - 5

45 (50-5) = 5n

n = 9

(45/5)